Typically, an electrostatic coating apparatus is used, for example, for coating automobile bodies. In contrast to conventional systems, the electrically charged spraying head is replaced by an arrangement of external electrodes at a high voltage potential. This arrangement is known to have substantial advantages when used with highly conductive spraying materials such as so-called water enamels (cf. German OS No. 34 29 075). Moreover, this arrangement eliminates considerable insulating problems since all lines carrying paint may be grounded as far back as the spraying head.
However, the problem with an apparatus having external electrodes is that it is extremely difficult to achieve a satisfactory degree of application, which is dependent upon satisfactory charging of the sprayed coating material, while preventing the coating material from contaminating the spraying device, electrodes and electrode holders. For this reason, the apparatus disclosed in German OS No. 34 29 075 has only two, three or,at the most, four charging electrodes, each of which is embedded in a plastic holder spaced radially from the external housing of the spraying head and projecting towards the object to be coated. Each of these holders contains a high voltage cable running to the respective electrode and is connected, at its rear end, to an annular element which is located upon the external housing and is also made of plastic. Although this design has proved itself in practice, it is impossible under certain operating conditions to overcome all of the problems aforementioned regarding the danger of contamination. Furthermore, as a result of the restriction to a maximum of four external electrodes, there is a danger of nonuniform "spray patterns" arising from paint concentrations in the vicinity of the electrodes.